Molded bearings having low friction mating surfaces



Aug. 27, 1963 I c. 3. WHITE 3,101,961

MOLDED BEARINGS HAVING LOW FRICTION MATING SURFACES driginal Filed June1e, 1955 2 Sheets-Sheet 1 INVENTOR 6%4rZas 5, jfd.

Aug. 27, 1963 c. 5. WHITE 3,101,961

MOLDED BEARINGS HAVING LOW FRICTION MATING SURFACES Original Filed June16, 1955 'EE-T 2 Sheets-Sheet 2 INVENTOR [/fiqf/es 5 Wiz'fe,

BY W, M "M United States Patent Ofiice 3,ll,%i Patented Aug. 27, 19633,101,961 MOLDED BEARINGS HAVING LOW FRICTION MATLIG SURFACES Char-HesS. White, Rte. 3, Box 454-I-I, Palrndale, Calif. Original applicationJune 16, 1955, Ser. No. 516,003, now

Patent No. 2,885,248, dated May 5, 1959. Divided and this applicationMay 4, 1 959, Ser. No. 810,911

' 7 Claims. (Cl. 287-52) This invention relates to bearings, andparticularly to a built-up type of bearing made from resinous, sinteredand like materials, and is a division of copending application, SerialNo. 516,003, filed on June 16, 1955, now Patent 2,885,248.

Various attempts have been made heretofore to employ plastic resinousmaterial for bearings which'for certain applications have provedsatisfactory. For heavy or concentrated loads, such bearings have provedinadequate, primarily because the material which provided strengthagainst flow had high friction characteristics.

In one form of the present invention, a thermosetting type of resinmaterial is employed which is shaped to the form of a mating bearingelement when in postsettable stage so that after it is shaped to matewith a bearing surface it may be hardened by the application of heat.The material is built up to provide strength against flow and distortionunder load and the bearing surface is preferably formed of an embeddedresinous material which has low friction characteristics so that littleresistance to initial breakaway is offered.

One method of forming the plastic insert for a ball and socket assembly,by Way of example, would be to employ circular fabric disks to form asolid background. Such disks are made of light canvas impregnated withphenoformaldehyde resin or a similar type of thermosetting resinousmaterial. A final layer of Teflon cloth is placed on the plurality oflayers which are then coldshaped in a semispherical form in a die set orsimilar device. This assembly is then placed in the cavities of a dieset of a type to which pressure and heat may be applied. The timeandheat are accurately regulated so as not to completely cure the resinmaterial but have it retained in a postsettable stage. The assembly thusmade has the Teflon cloth physically bonded thereon by the passage ofthe resinous material through the interstices of the cloth. The surfaceof resinous material formed over the threads of the Teflon cloth isremoved by some simple process, such as vapor blasting and the like. Afluid under pressure containing a fine abrasive is directed over thesurface to remove the resinous material and expose the threads of theTeflon cloth material.

During the molding stage, the cavities and mating die portions are soshaped as to provide projections and recesses on opposite sides of theinserts. The recessed areas are provided on the bearing surface toretain a lubricant therein, while the mating projections on the oppositeside engage recesses in the supporting member which positions andanchors the insert against a turning movement. It is to be understoodthat a bonding material may be placed between the surfaces of the insertand supporting member to further securely anchor the insert in place.The insert is placed between a ball and socket of a joint and pressureis applied between the ball, insert and the socket in an amountdepending upon the size of the joint to cause the material of the insertto form itself accurately to the ball and the cavity of the socket.While in pressure relationship, heat is applied at a temperaturesufficient to set the resinous material to have the insert hardened whenin mating relationship with the bearing surface. When lubrication isdesired, a lubricant is placed within the recesses of the insert and themating surface of the ball before the pressure is applied to theassembly. In certain applications the Tefion material will provide thenecessary lubricating features since it is of the low friction type andno noticeable amount of increased force will be required for initiallybreaking the joint.

Accordingly, the main objects of the invention are: to provide a bearingmade of a material sufficient to resist deforming when loaded and havinga low friction material embedded in the bearing face thereof; to providea bearing made of a resin material having a low friction resinousmaterial embedded in its bearing surface which reduces resistance tobreak-away and provides a cool operating bearing surface; to construct abearing of sintered material having embedded in the interstices thereofa. low friction material which provides low friction operatingcharacteristics to the bearing; to form a bearing of a backing materialin postsettable stage having embedded in the mating bearing surface alow friction resinous material, all of which is formed to a matingbearing surface under pressure and hardened by the application of heat,and, in general, to provide a bearing made of a formable material havingembedded therein a low friction material, all of which is simple inconstruction and economical of manufacture.

Other objects and features of novelty of the invention will bespecifically pointed out or will become a parent when referring, for abetter understanding of the invention, to the following descriptiontaken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a sectional view of a ball and socket type of bearing,embodying features of the present invention;

'FIG. 2 is a broken sectional view of a ball and socket joint, similarto the joint illustrated in FIG. 1, showing another form thereof;

[FIG 3 is a sectional view of a joint, similar to that illustrated inFIG. 2, showing a further form which the joint may assume;

FIG. 4 is a view of a splined shaft and socket having a bearing sleevetherebetween to provide a perfect engagement between the splined areasthereof;

FIG. 5 is a sectional view of a plastic insert employed in the ball andsocket bearing of FIG. 1;

FIG. 6 is a broken sectional view of the structure illustrated in FIG.5, taken on the line 6--6 thereof;

FIG. 7 is a plan view of an impregnated disk a plurality of which formthe body portion of the insert of the hearing illustrated in FIGS. 2 and3;

FIG. 8 is a sectional view of a plurality of the disks illustrated inFIG. 7 shown in stacked relationship;

FIG. 9 is a view of the stacked disks of FIG.I 8 after being cold formedto semispllerical shape;

FIG. 10 is a view of an insert molded from the assembly of FIG. 9;

FIG. 11 is a plan view of the structure illustrated in FIG. 10;

FIG. 12" is a sectional view of the structure illustrated in FIG. 10,taken on the line 12-12 thereof;

FIG. 13 is an enlarged, broken sectional view of the bearing surface ofthe inserts illustrated in FIGS. 5 to 12 inclusive;

FIG. 14 is a perspective 'view of a heavy bearing embodying features ofthe present invention;

FIG. 15 is a sectional view of the structure illustrated in FIG; 14,taken on the line 15-15 thereof;

FIG. 16 is an enlarged, broken plan view of a surface of a bearingformed from sintered particles;

FIG. 17 is a view of :a bearing, similar to that illustrated in FIG. 14,when in cylindrical shape;

FIG. 18 is a broken sectional view of the structure illustrated in FIG.17, taken on the line 1818 thereof, and

'FIG. 19 is a reduced side view of the structure of 3 FIG. 4, showingthe slight taper to the engaged splines lengthwise of the shaft.

In FIG. 1 a ball and socket joint 21 is illustrated mounted on a yoke 22having a spindle thereon (not shown) for supporting. a front Wheel of avehicle. In FIG. 2 a ball and socket joint 23- is illustrated mounted onthe bottom end of the yoke 22, both of the joints being shown inposition of assembly, the joint 21 being disposed at an angle to thevertical. The joint 21 comprises a truncated ball 24 having a stud 25thereon provided with a tapered. portion 26 terminating in a threadedend 27. The stud is secured by a nut 28 to one arm of the yoke 22. Adished stamping 29 mates with an apertured dished stamping 31 about theball 24,, the two stampings being assembled on a supporting arm 32 ofthe vehicle by suitable means, herein illustrated as by bolts 33. Asealing element 34 is sealed to the dish-shaped stamping 31 and the stud25 of the ball 24 to prevent the entrance of dirt and grime to thecavity about the ball. A pair of oppositely disposed, truncated, hollowspherical inserts 35 is mounted about the ball in pressure engagementwith the stampings 29 and 31.

The ball and socket joint 23 of FIG. 2 embodies a stud 36, similar tothe stud 25, having a socket 37 thereon in place of the ball 24. Acup-shaped element 38 surrounds the socket 37 and contains a truncatedsolid ball 39 on a stem 41 which is mounted on a supporting arm 42 ofthe vehicle by a Washer 43 and nut 44. A sealing element 34 seals thecup-shaped element 38 and the stud 36. Between the socket '37 and theball 39, an insert 45 is provided, constructed in a manner hereinafterdescribed.

In FIG. 3 a similar ball and socket joint 46 is illustrated, employingthe same stud 36 and socket 37 but having a hollow ball 47 provided on astamping 48. A dish-shaped stamping 49 mates with the stamping 48 andpermits a seal to be employed between the stamping 48 and the stud 36.An insert 45 is employed between the ball portion 47 and the socket 37.

Referring to FIGS. to 13 inclusive, the manner of constructing theinserts 35 and 45 will now be described in detail. The main body portionof the insert may be of any material known in the art to be suitablewhich has a presettable stage so that it may be formed to the shape of amating bearing surface and set thereafter. In the example shown, theinsert is made up of a plurality of layers of cloth material, such aslight canvas impregnated with a suitable resinous material. The layers51 are preferably cut in circular form and stacked upon each other. Thetop layer 52 which is to form the bearing surface is of Teflon clothmaterial which will be physically bonded to the resinous material of thedisks 51. It is to be understood that the mentioning of thephenorformalde'hyde material impregnating the disks 51 was by way ofexample since it is well known to those skilled in the art that othertypes of thermosetting resins may be substituted therefor. It is to befurther understood that the resin material may be used to form the bodyof the insert without the cloth material embedded therein and with thelayer of Teflon or like low friction material embedded in the bearingsurface.

The Teflon material 51 is a type of resin which will withstand 600operating temperature. This is desirable to produce bearings which mustwithstand such temperature. A resin for the body would be employed whichis moldable to a desired shape at such high temperatures but which will,upon cooling, become permanently set. The Teflon cloth, when employed incombination with such thermoplastic materials, will produce the lowfriction type of surface to the bearing and will withstand therewith thehigh operating temperatures. The Teflon material itself could not beemployed successfully to construct such a bearing since above 600 F. itbecomes jelly-like inform and flows under pressure when in a cold stage.The combination, however, of the Teflon cloth on the surface of abearing constructed of either thermoplastic or thermosetting materialprovides the desired low friction characteristic, While the solidbacking body portion prevents any deforming or flow of the material. TheTeflon cloth herein referred to is by way of example, since other lowfriction material, such as nylon and the like, may be substituted forthe Teflon on the bearing surface of the insert or bearing body.

Powdered Teflon, nylon and like substances were first employed upon thesurface of the insert but, due to the cold flowing of these materialsunder pressure, they could not be retained in' contact with the matingbearing surface. By employing such materials in sheet form, such aswoven cloth, perforated sheets, or sheets having granular surface, orfibers woven into a porous material having interstices so that aphysical bond could occur between such sheet material and the baclcingmaterial, satisfactory retention of the low friction material isobtained. The physical bonding of the low friction material by thebacking material prevents the cold flowing of the Teflon or likematerial and the low friction characteristics are maintained between themating bearing surfaces. Before the final presetting stage, it isdesirable to remove the film of bonding resin material from the surfaceof the low friction material by some suitable means, as by air blastingor the like, as hereinabove mentioned. In some types of bearings, the"film of bonding resin material will wear rapidly away, exposing the lowfriction material which will then be in contact with the mating bearingsurface. When employing the Teflon and like materials, providing the lowfriction characteristics, the resulting hearing will have a low frictionbreak-away, coupled with the antifriction properties which are desirablebetween the bearing surfaces.

After the several layers 51 haave been assembled with the top layer 52of Teflon or like material, the assembly is then cold shaped to asemispherical form, as illustrated in FIG. 9. These assemblies are thenplaced in a multieavity mold and shaped to the form illustrated in FIGS.10, 11 and 12 under pressure and heat, the heat being applied for asuflicient time to cure the resinous material to the presettable stage.The mold for the insert 45 is so formed as to provide slots 54 on theouter face of the insert disposed at right angles to each other andinward projections 55 on the inner face in alignment with each other. Asillustrated in FIGS. 2 and 3, the balls 39 and 47 are provided withright angularly disposed slots 56 for receiving the inward projections55 to thereby locate the insert on the ball surface and prevent it fromrotating. Preferably a bonding material 57 is provided therebetween tosecurely bond the insert on the ball surface. A lubricant may be placedin the facing slots 54 of the insert before pressure is provided betweenthe socket 37 and the ball 39 sufliciently to deform the presettablematerial of the insert 45 to the exact shape of the mating surface ofthe socket and ball. Heat is then applied to the assembly when underpressure to finally cure the material of the insert to have it retainthe exact shape of the spherical sections of the socket 37 in bearingrelationship therewith. While it is a simple expedient in the art toaccurately finish and polish a ball surface, it is difiicult to maintainexact diameters so that a metal ball could accurately be machined tomate with a socket surface. By accurately molding the insert to the ballor socket bearing surface, accurate mating relationship occurs over theentire mating area without the ball and socket being of exact matingdiameters.

The insert 35 is constructed in a similar manner, the interior of theinsert being the bearing surface for the ball 24. A pair of the sectorelements 35 is assembled on the ball, one from the top and the otherfrom the bottom and pressure is provided by the plates 29 and 31 beforeand during the time heat is applied to set the resinous material whichthereafter remains accurately shaped to the ball. In the form hereinillustrated, slots 54 are disposed in the inner face of the insert andthe projections 55 are omitted, although these could be provided. Asuitable bonding material 57 secures the inserts to the dishshapedportions of the plates 29 and 31. The shaping of the inserts to the ballwith pressure on the insert mate-rial when in presettable stage and thehardening of the inserts thereafter is illustrated, described andclaimed in the copending application of Charles S. White, Serial No.396,893, filed December 8, 1953, now Patent No. 2,835,- 521 for BallJoint Bearing Structure.

The invention is not limited to inserts for ball and socket jointshereinabove described by way of example, but as shown in FIGS. 4, 14 to19 inclusive, the invention has many other applications. In FIGS. 4 and19, for eX- ample, a tapered spline shaft 61 is to be mated within thetapered splined aperture .of a supporting element 62 without any playtherein and with surface engagement throughout the entire mating area.In such an arrange merit, a splined sleeve 63, made of a thermosettingresin in the presettable stage, is shaped to mate with the splines ofthe elements 61 and 62 and inserted therebetween. Upon the applicationof pressure longitudinally between the elements 61 and 62 on thematerial of the splined sleeve 63, the material is formed to engage theentire mating surfaces between the spline projections and recesses andwhen heat is applied to the assembly the material of the sleeve ishardened and a substantially solid driving relationship results betweenthe shaft 61 and the supporting element 62.

In FIG. 13 it will be noted that the resinous material 64 of the insert51 is forced about the threads 65 and 66 of the Teflon cloth materialwhich physically bonds the threads to .the resin and provides a film ofresin over the outer surface of the threads. This film of material isremoved by the vapor blast process or other means as hereina'bovereferred to before the insert is finally shaped and hardened in thesocket assembly.

In FIG. 16 a further form of the invention is illustrated, that whereinparticles 67 of brass, iron and the like are siutered together in amanner well known in the art, but in the present instance is sintered inthe presence of the Teflon or like material 68 which fills theinterstices between the particles 67. With this arrangement, the Teflonor like material provides the low friction chazracteristics for thebearing surface, which thereby eliminates the use of a liquid lubricantcommonly employed.

In FIGS. 14 and 15, a further form of the invent-ion is illustrated,that wherein a heavy journaled sleeve is disclosed similar to thatemployed :on railway cars. The backing 69 of the bearing is constructedin a well known manner of resinous material of suificient strength anddurability to support a load and prevent the cold flow thereof. Thesurface of the material 71 is made from a sheet of Teflon or likematerial, which is embedded therein in the manner hereina'bove referredto, which provides the low friction characteristic to the engagingsurface of the bearing, which thereby reduces the heavy break-away forcewhich would otherwise be required.

In FIGS. 17 and 18 a similar form of the invention is illustrated, thatwherein a resinous backing material 72 is bonded to a metal sleeve 73having a thread 74 on the outer surface. The inner bearing surface 75has the Teflon or like sheet as hereinabove described embedded therein.The two units are assembled together and threaded within a sleeve 76which supports the bearing and prevents the endwise movement thereof.

It will thus be seen that the bearings hereinabove described are formedwith a backing or body portion which resists deformation under load. Theinterstices of the bearing face are filled with Teflon or like materialwhich is physically anchored to the body material when the basematerialis molded to the shape of the bearing and hardened. When the bearing ismade of sintered particles, the Teflon or like material, when heated,forms a jell which fills all of the interstices between the particles,to thereby provide the low friction characteristic to the resultingbearing element. When the body material is a resinous material, theTeflon or like material is preferably in woven or sheet form, havinginterstices through which the resin may pass to physically anchor thematerial thereto. Such bearings are capable of withstanding load shockswhile having a desired low friction characteristic without the presenceof a lubricant. Recesses, however, may be provided in the bearingsurface in which a lubricant may be retained to further reduce thefriction engagement between the bearing surfaces.

What is claimed is:

l. A spline assembly comprising a member having a cylindrical aperturecontaining lands and grooves forming a spline, a cylindrical memberhaving lands and grooves on its outer surface with the lands of onemember disposed in the grooves of the other member, the grooves andlands being so proportioned as to have a substantial space therebet-weenand with the lands so related as to prevent relative rotation betweenthe members, and a hard low friction material disposed between saidlands Within said grooves filling the space therebetween and preventingrelative rotary movement between the members.

2. The subject matter as claimed in claim 1, wherein said low frictionmaterial is fixed to one of said members and disposed in low frictionrelation with the other said member.

3. The subject matter as claimed in claim 2, wherein the low frictionsurface of said material is composed of interrelated Teflon fibers.

4. A spline assembly comprising a support member having a splinedcylindrical aperture, a splined cylindrical shaft member extendingwithin said aperture with the splines of one member nested in the grooveof the other member with a substantial space therebetween and with thesplines overlapping so as to prevent any substantial relative rotationbetween the members, and a hard low friction material disposed withinthe spaces and. preventing any rotational movement between the members.

5. The subject matter of claim 4, wherein at least the surface of saidmaterial has low friction characteristics disposed in intimateengagement with the splines of one of said members.

6. The subject matter as recited in claim 5, wherein said surfacecontains Teflon.

7. Subject matter as recited in claim 4 wherein the cylindrical apertureand shaft are tapered for forming the material therebetween whenrelative longitudinal pressure is applied between the members.

References Cited in the file of this patent UNITED STATES PATENTS536,184 Case Mar. 26, 1895 1,370,073 Utz et all. Mar. 1, 1921 2,199,926Swennes May 7, 1940 2,259,460 Dexter Oct. 21, 1941 2,317,070 TourneauApr. 20, 1943 2,339,967 Brubaker Feb. 5, 1946 2,443,688 McFarland June22, 1948 2,448,483 B-assett Aug. 31, 1948 2,699,656 Anderson et al Jan.18, 1955 2,705,691 Panagrossi et al Apr. 5, 1955 2,773,781 Rodman Dec.11, 1956 2,879,091 Baker Mar. 24, 1959 2,960,348 Sarowski et al Nov. 15,1960 3,017,209 Thomas Jan. 16, 1962

1. A SPLINE ASSEMBLY COMPRISING A MEMBER HAVING A CYLINDRICAL APERTURECONTAINING LANDS AND GROOVES FORMING A SPLINE, A CYLINDRICAL MEMBERHAVING LANDS AND GROOVES ON ITS OUTER SURFACE WITH THE LANDS OF ONEMEMBER DISPOSED IN THE GROOVES OF THE OTHER MEMBER, THE GROOVES ANDLANDS BEING SO PROPORTIONED AS TO HAVE A SUBSTANTIAL SPACE THEREBETWEENAND WITH THE LANDS SO RELATED AS TO PREVENT RELATIVE ROTATION BETWEENTHE MEMBER, AND A HARD LOW FRICTION MATERIAL DISPOSED BETWEEN SAID LANDSWITHIN SAID GROOVES FILLING THE SPACE THEREBETWEEN AND PREVENTINGRELATIVE ROTARY MOVEMENT BETWEEN THE MEMBERS.